LONDON, May 8 (Reuters) - HSBC HSBC.L shocked markets with an unexpectedly large $400 million loss linked to a fraud case involving a British mortgage lender this week, turning the spotlight to banks and their deep involvement in the private credit sector.

HSBC's loss related to its loan to an Apollo-backed unit Atlas SP and its financing of Market Financial Solutions (MFS) was more about fraudulent practices than the ongoing liquidity and profitability concerns in private credit.

Yet, the loss showed why regulators worldwide have become more concerned about banks' exposure to the $3.5 trillion private credit industry, highlighting the often indirect and opaque nature of the lending.

Global financial watchdog, the Financial Stability Board (FSB), issued a warning around increasing risks stemming from banks' expanding connections with the private credit market.

The FSB cited concerns over potential rising defaults, high concentration of investments, and a general lack of transparency within the sector.

Reuters analysed one interesting shift as a result of these strains, a rebalancing of the lending landscape between private funds and conventional banks.

The study found some U.S. borrowers are shifting away from private credit and opting for bank-led syndicated loans as financing terms in the private credit market become less competitive and traditional bank financing becomes considerably cheaper for certain companies.

More earnings from publicly listed business development companies (BDCs) illustrated the impact of the software sector strains on private credit. Reuters reported that leading asset managers Blackstone BXSL.N and BlackRock both reduced the valuation of their private credit funds in the first quarter.

BlackRock, for instance, cut the value of one fund by 5%, while Blackstone's Secured Lending Fund saw its net asset value per share drop by 2.4%.

Blue Owl's largest publicly traded private credit fund OBDC.N plans to decrease its exposure to the software sector, pointing to the industry's re-assessment of valuations, growth prospects and increased competition in software lending.

To be fair, while concerns about potential private credit defaults exist, a widespread wave of maturities requiring immediate refinancing is not imminent. A Reuters analysis, based on U.S. Securities and Exchange Commission filings from 74 private credit funds, suggests that significant debt maturity walls for private credit borrowers are generally further out into 2027 and 2028.